CE_ConceptSummary

Concept Summary

• A small number of atoms combine to make a large variety of things (molecules).
• Some materials change in a way that rearranges the atoms into new molecules (chemical change/combustion).
• Some materials change in a way that preserves the original molecule(s) (physical change/distillation).
• Hydrocarbons have predictable properties, based on their composition (alkane series/vaporization/propellants/VOC).
• Nature provides hydrocarbon resources in a variety of ways (renewable & nonrenewable fuels).
• Hydrocarbon combustion involves predictable chemical reactions (balanced equations, fire triangle, pollution).

Some of the most important chemical fuels are part of a family called alkanes. The alkane series includes molecules built entirely of carbon and hydrogen (no other atoms) with only single bonds (no double bonds). Methane is the simplest of the series, using exactly one carbon atom, ethane is next, using exactly two carbon atoms, and propane and butane follow. Use the molecular model kit to make as many different types of alkanes as you can.

After you are comfortable making the molecules, consider these questions:

• Can you draw the molecule (in its straight-chain form)?
• Can you count the number of atoms in the molecule?
• What is the formula of the molecule?